Oilseed Brassica is being grown as an increasingly important oilseed crop in many parts of the world. As a source of vegetable oil, it presently ranks behind only soybeans and palm and is virtually tied with sunflowers for the number three position of commercial importance. The oil is used as both a salad oil and a cooking oil throughout much of the world.
In its original form Brassica oil, often known as rapeseed oil, was found to have deleterious effects on human health due to its relatively high level of erucic acid which commonly is present in native cultivars in concentrations of 30 to 50 percent by weight based upon the total fatty acid content. In the past plant scientists identified a germplasm source of low erucic acid rapeseed oil. See, Chapter 6 entitled "The Development of Improved Rapeseed Cultivars" by B. R. Stefansson from "High and Low Erucic Acid Rapeseed Oils" edited by John K. G. Kramer, Frank D. Sauer, and Wallace J. Pigden, Academic Press Canada (1983).
In Canada, plant scientists focused their efforts on creating so-called "double-low" varieties which were low in erucic acid in the oil and low in glucosinolates in the solid meal remaining after oil extraction (i.e., an erucic acid content of less than 2 percent by weight based upon the total fatty acid content, and a glucosinolate content of less than 30 micromoles per gram of the oil-free meal). These higher quality forms of rape developed in Canada are known as canola.
In contrast, European scientists worked to achieve only "single-low" types which were low in erucic acid, but did not attempt to improve the quality of the solid meal which retained a glucosinolate content of about 100 micromoles per gram of oil-free meal. The result of this major change in the fatty acid composition of rapeseed oil was the creation of a new oil profile which often contained approximately 8 to 15 percent by weight of alpha-linolenic acid, approximately 62 percent by weight of oleic acid based upon the total fatty acid content, and approximately 6 percent or more by weight of saturated fatty acids in the form of stearic acid and palmitic acid based upon the total fatty acid content. Since the overall percentage of oil in the seed did not change appreciably when the new low erucic cultivars were developed, it appeared that the erucic acid oil component had been redirected into other fatty acids within the oil. See, Chapter 7 entitled "The Introduction of Low Erucic Acid Rapeseed Varieties Into Canadian Production" by J. K. Daun from the previously identified Academic Press Canada (1983) publication; "Prospects for the Development of Rapeseed (B. napus L.) With Improved Linoleic and Linolenic Acid Content" by N. N. Roy and A. W. Tarr, Plant Breeding, Vol. 98, Pages 89 to 96 (1987); and "Genetic Control of Fatty Acid Composition in Oilseed Crops" by R. K. Downey and D. G. Dorrell, Proc. Flax Inst. U.S.A., Vol. 47, No. 3, Pages 1 to 3.
Over the years scientists have attempted to improve the fatty acids profile for canola oil. See, for instance, Chapter 10 by Gerhard Robbelen entitled "Changes and Limitations of Breeding for Improved Polyenic Fatty Acids Content in Rapeseed" from "Biotechnology for the Oils and Fats Industry" edited by Colin Ratledge, Peter Dawson, and James Rattray, American Oil Chemists' Society (1984).
"Genetical and Physiological Investigations on Mutants for Polyenoic Fatty Acids in Rapeseed, Brassica napus L." by G. Robbelen and A. Nitsch appearing in Z. Planzenzuchtg., 75, Pages 93 to 105 (1975), and "Opportunities and Problems in Modification of Levels of Rapeseed C.sub.18 Unsaturated Fatty Acids" by G. Rakow and D. I. McGregor appearing in J. Am. Oil Chem. Soc. 50(10), Pages 400 to 403 (1973) are representative disclosures of a rapeseed mutant that includes a lesser than usual quantity of alpha-linolenic acid in the oil.
U.S. Pat. No. 4,948,811 discloses a salad/cooking oil wherein less desirable fatty acid components are physically separated from other fatty acid components following removal of the oil from rapeseeds. An operative straightforward means to provide the presently claimed highly advantageous distribution of fatty acids in the endogenous rapeseed oil was totally absent.
International Publication No. WO90/10380, published Sep. 20, 1990, and European Patent Application No. 0 343 753, entitled "Production of Improved Rapeseed Exhibiting an Enhanced Oleic Acid Content" published Jul. 12, 1989, disclose the production of rapeseeds that include a greater than usual concentration of oleic acid in the oil. A similar disclosure is found in commonly assigned U.S. patent application Ser. No. 286,708, filed Dec. 20, 1988. The presently claimed highly advantageous distribution of fatty acids was not disclosed.
International Publication No. WO91/15578, published Oct. 17, 1991, entitled "Production of Improved Rapeseed Exhibiting a Reduced Saturated Fatty Acid Content" discloses the production of a rapeseed that includes a lesser than usual concentration of stearic and palmitic acids in the oil. A similar disclosure is found in U.S. Pat. Nos. 5,387,758, 5,434,283 and 5,545,821. The presently claimed highly advantageous distribution of fatty acids was not disclosed.
International Publication No. WO92/03919 published Mar. 19, 1992, entitled "Seeds, Plants and Oils With Altered Fatty Acids Profiles" discloses an effort to modify the fatty acid distribution in an oil obtained from rapeseeds. The presently claimed highly advantageous distribution of fatty acids was not disclosed.
As reported in U.S. Pat. Nos. 4,517,763; 4,658,084; and 4,658,085; hybridization processes suitable for the production of rapeseed are known wherein herbicide tolerance is utilized.
The need has remained for an edible endogenous vegetable oil obtained from Brassica seeds in the absence of hydrogenation or other chemical or physical modification that possesses an improved overall distribution alpha-linolenic acid in a low concentration, oleic acid in a high concentration, saturated fatty acids in an extremely low concentration, and erucic acid in a low concentration simultaneously as claimed herein. In view of the highly complex nature of the molecular elongation and desaturation pathways that are operative during fatty acid formation in Brassica oilseeds, the achievement of this goal has not been realized by skilled researchers in the past as evidenced by the data reported in the above-identified publications.
It is an object of the present invention to provide an improved mature Brassica oilseed capable of yielding an edible endogenous vegetable oil having a novel improved distribution of fatty acids following simple crushing and extraction.
It is an object of the present invention to provide an oilseed Brassica plant having satisfactory agronomic characteristics which upon self-pollination is capable of forming Brassica oilseeds that yield an endogenous vegetable oil having a novel improved distribution of fatty acids following simple crushing and extraction.
It is another object of the present invention to provide an improved edible vegetable oil having a novel improved distribution of fatty acids formed by the simple crushing and extraction of Brassica oilseeds in the absence of hydrogenation or other chemical or physical modification.
It is a further object of the present invention to provide an improved endogenous vegetable oil derived from Brassica oilseeds in the absence of hydrogenation or other chemical or physical modification of good flavor having improved health and nutritional characteristics combined with attractive stability characteristics that is produced on a highly economical basis.
It is another object of the present invention to provide mature Brassica oilseeds capable of yielding an edible endogenous oil having an improved distribution of fatty acids that renders it suitable for a number of different end uses thereby simplifying the handling, crushing and refining requirements for such seed product.
It is yet another object of the present invention to provide on an expeditious and economically feasible basis a novel endogenous oil derived from Brassica oilseeds that is well suited for a wide range of end uses thereby simplifying storage and inventory considerations for those who supply the improved vegetable oil of the present invention.
These and other objects and advantages of the invention will be apparent to those skilled in the art from a reading of the following description and appended claims.